Hot gas defrosting refrigerating apparatus



Feb. 20, 1962 AUNE 3,021,693

HOT GAS DEFROSTING REFRIGERATING APPARATUS Filed May 21, 1959 dhonoona CJCDQ Fig. i

Inventor Cllbert LU. Qunxe 3y ,we Z -g d (liken-Legs 3,021,693 HGT GAS DEFRUSTENG REFRIGERATHJG APPARATUS Albert W. Anne, Minneapolis, Minn, assignor to Me- Qua i, Ind, Minneapolis, Minn, a corporation of Minneso 21 Filed May 21, 1959, Ser. No. 814,860 3 Qiaims. (Cl. 62-278) evaporated, whereby the returning refrigerant is rendered harmless to the compressor.

An object of the present invention is to provide a hot gas defrosting refrigerating apparatus of the nature aforesaid, wherein heat from the hot defrosting gas is supplied to the returning liquid refrigerant during the defrosting periods only so that during a refrigerating period the refrigerant will not be substantially affected, adversely to the cooling functioning of the apparatus, by reason of the heat previously supplied to the returning liquid refrigerant by the hot gas during defrosting.

Another object of the invention is to furnish in a refrigerating apparatus of the present character a simple, durable, compact, inexpensive and efficient device providing both a liquid refrigerant accumulator in the refrigerant return line and liquid-refrigerant reevaporating medium adapted to effect the transfer of heat from the hot gas in the hot gas defrost line to the returning liquid refrigerant as it enters the accumulator and after its accumulation therein.

Other objects of the invention reside in the novel combination and arrangement of parts and in the details of construction hereinafter illustrated and/or described.

In the drawing:

FIG. 1 is an elevational view principally in diagram illustrating an apparatus constructed in accordance with my invention, the same including a device constituting both a liquid refrigerant accumulator and means for effecting the transfer of heat from gas in the hot gas defrost line to the liquid refrigerant entering and accumulated within said device.

FIG. 2 is an end view in detail of said device.

FIG. 3 is a vertical sectional view of said device taken as on the line 33 of FIG. 2.

Referring to the drawing, it will be seen that the illustrated hot gas defrosting refrigerating apparatus includes the familiar compressor 10, condenser A with coil 11 and receiver 12, and evaporator B with coil 13 and fan 14. As usual, a compressed gas feed line 15 leads from the discharge side of the compressor 10 to the coil 11 of the condenser A, and a refrigerant supply line 16 extends from the receiver 12 of the condenser A to the coil 13 of the evaporator B, said refrigerant supply line 16 having a conventional expansion valve 17 therein adjacent to said evaporator coil 13.

A refrigerant return line C leading from the evaporator B to the suction side of the compressor 10 includes the casing 13 of a combination liquid refrigerant accumulating and reevaporating device D, there being further included in said refrigerant return line C a conduit section 19 extending from the evaporator B to an inlet fitting 20 in the casing 18 of said device D and a conduit section end of the outlet nipple 22 3,@Zi,% Patented Feb. 26, 1952 21 extending from an outlet fitting 22 in said casing 18 to the compressor 10.

A hot gas defrost line E leading from the compressed gas feed line 15 to the evaporator B includes a conduit section 23 having an intermediate portion 24 looped in the interior of the casing 18 of said device D. Further included in said hot gas defrost line E is a conduit section 25 extending from said compressed gas feed line 15 to the end 26 of said looped conduit section 23 and still further included in the hot gas defrost line B is a conduit section 27 extending from the other end 28 of said looped conduit section 23 to the refrigerant supply line 16, the connection between said last defrosting conduit section 27 and the refrigerant supply line 16 being made at a point in said supply line 16 beyond the expansion valve 17 therein next to the coil 13 of the evaporator B so that hot gas from the hot gas defrost line B will enter the evaporator B and heat the coil 13 thereof to defrost the same. A solenoid valve 29 in the hot gas defrost conduit section 25 is electrically connected with a source of'current and a timing mechanism (notshown) of any con ventional or suitable form for the purpose of periodically opening and closing the said solenoid valve 29 whereby, when said valve 29 is open, the hot gas discharge from the compressor 10 will pass through the conduit sections 25, 23 and 27 of said hot gas defrost line E to the coil 13 of the evaporator B, instead of passing through the coil 11 and receiver 12 of the condenser A and then through the refrigerant supply line :16 to the coil 13 of the evaporator B.

The casing 18 of the liquid refrigerant accumulator and reevaporating device D is of capsular construction in two complementing parts 18*, 18 telescopically connected oneto the other and welded together as at 39, the fabricated casing 18 having a main cylindrical wall 31 and end walls 32, 33, said casing 18 being adapted to be disposed in a horizontal position. The inlet fitting 20 in said casing 18 is an upright nipple extending through the cylindrical casing wall 31 near the end wall 32 of the casing, said nipple 20 opening into the upper portion of the casing and being welded to said cylindrical wall 31 as at 34. The outlet fitting 22 in the casing 18 includes a nipple 22 extending downwardly into the casing through the cylindrical wall 31 at the top thereof, said nipple 22 being welded to said wall 31 as at 35. Said outlet fitting 22 further includes a tubular gooseneck extension 22*. This extension 22 of U-shaped form has an upright reach 36 telescopically joined at its upper end with the lower The other reach 37 of the gooseneck extension 22 upstands from the bend 38 of said extension 22 and opens into the upper portion of the casing 18 near the top thereof where it receives only gaseous refrigerant from the interior of the casing. The bend 38 of the gooseneck extension 22 is bottomed on the bottom of the casing 18 and, near the lowermost point of the bend 38, said bend is formed with a metering orifice 39 through which liquid refrigerant and oil (if oil is present in the apparatus) may be drawn from the casing 18 and evaporated or finely broken up for safe introduction into the compressor 10.

The conduit section 23, incorporated in the device D and providing an element of the hot gas defrost line E, is U-shaped, having'its looped intermediate portion 24 located within the casing 18 and having its end portions 26, 23 extending through the end wall 32 of said casing, said end portions 26, 28 of the looped conduit section being welded to the casing as at 46. The axes of the two branches 24 and 24 of the looped intermediate portion 24 of said conduit section 23 and the axis of the inlet nipple 20 in the casing 18 lie in a common vertical plane. The lower branch 24 of said looped conduit portion 24 is disposed near the bottom of the casing 18 at least partly below the liquid refrigerant level normally obtaining therein, and the said upper branch 24 of said looped conduit portion 24 is disposed at least partly above such liquid level. Thus, said lower branch 24 of the looped conduit portion 24 will be at least partly submerged in the liquid refrigerant which has accumulated in the lower portion of the casing 18, and the upper branch 24 of said looped conduit portion 24, located directly beneath the inlet nipple 24] in the casing 18, will have at least a portion thereof bare and in position to intercept the liquid refrigerant entering said casing through said inlet nipple Accordingly, it will be understood that the hot gas passing through the hot gas defrost line E will be brought, in the looped portion 24 of the conduit section 23, into heat exchange relation with the liquid refrigerant flowing into the casing 18 and with the liquid refrigerant which has accumulated within th casing. Consequently, there is an effective flash transference of heat from the hot defrosting gas to the returning refrigerant during each defrosting period in the operation of the apparatus. And, during each refrigerating period, there is no retention in the device D of heat, previously acquired fiom the hot defrosting gas, in such amount as to substantially affect adversely the refrigerating capability of the apparatus.

From the foregoing, it will be readily comprehended that I have provided in a hot gas defrosting refrigerating apparatus a construction well meeting the objectives of the invention.

Changes in the specific form of the invention, as herein described, may be made within the scope of what is claimed without departing from the spirit of the invention.

Having described the invention, what is claimed as new and desired to be protected by Letters Patent is:

1. Refrigerating apparatus comprising a compressor, a condenser connected with the exhaust side of the coinpressor, an evaporator, a refrigerant feed line leading from the condenser to the evaporator for cooling the evaporator during refrigerating periods thereof, a hot gas defrost line leading from the exhaust side of the compressor to the evaporator for heating said evaporator during defrosting periods, a refrigerant return line leading from the evaporator to the suction side of the compressor, means associated both with said return line and said hot gas defrost line for accumulating therein liquid refrigerant returning from the evaporator and for supplying heat to said liquid refrigerant derived in exchange from hot gas in the hot gas defrost line to reevaporate such returning refrigerant during defrosting periods of the evaporator, said means comprising an elongated casing adapted to be disposed horizontally, said casing having an inlet leading thereinto at its upper portion near one end thereof and having an outlet leading therefrom at its upper portion adjacent the other end thereof, said inlet and outlet being connected into said refrigerant return line, said casing being provided with a conduit section having a looped U-shaped portion contained within the interior of the casing, the branches of said looped portion of said conduit section extending longitudinally of the casing, one branch being located adjacent to the bottom of the casing at least partly beneath the normal liquid refrigerant level therein, the other branch being located adjacent to the top of the casing at least partly above said liquid level in position beneath said inlet in the path of liquid refrigerant entering said casing via said inlet, said looped conduit section being connected at its ends into the hot gas defrost line of said apparatus.

2. Refrigerating apparatus comprising a compressor,

a condenser connected with the exhaust side of the compressor, an evaporator, a refrigerant feed line leading from the condenser to the evaporator for cooling the evaporator during refrigerating periods thereof, a hot gas defrost llne leading from the exhaust side of the compressor to the evaporator for heating said evaporator during defrost- 1ng periods, a refrigerant return line leading from the evaporator to the suction side of the compressor, means associated both with said return line and said hot gas defrost line for accumulating therein liquid refrigerant returning from the evaporator and for supplying heat to said liquid refrigerant derived in exchange from hot gas in the hot gas defrost line to reevaporate such returning refrigerant during defrosting periods of the evaporator, said means comprising a casing having an inlet leading thereinto at its upper portion and having an outlet leading therefrom at its upper portion, said inlet and outlet being connected into said refrigerant return line, said casing being provided with a conduit section having a portion looped into the interior of the casing, said looped portion of said conduit section having a lower branch disposed at the lower portion of the casing and having an upper branch disposed at the upper portion of the casing directly be neath said inlet in position to intercept the liquid refrigerant flowing into said casing via said inlet, said conduit section being connected at its ends into the hot gas defrost line of said apparatus.

3. Refrigerating apparatus comprising a compressor, a condenser connected with the exhaust side of the compressor, an evaporator, a refrigerant feed line leading from the condenser to the evaporator for cooling the evaporator during refrigerating periods thereof, a hot gas defrost line leading from the exhaust side of the compressor to the evaporator for heating said evaporator during defrosting periods, a refrigerant return line leading from the evaporator to the suction side of the compressor,

eans associated both with said return line and said hot gas defrost line for accumulating therein liquid refrigerant returning from the evaporator and for supplying heat to said liquid refrigerant derived in exchange from hot gas in the hot gas defrost line to reevaporate such returning refrigerant during defrosting periods of the evaporator, said means comprising a casing having an inlet leading thereinto at its upper portion and having an outlet leading therefrom at its upper portion, said inletand outlet being connected into said refrigerant return line, said casing being provided with a conduit section having an intermediate portion contained within the interior of the casng, a part at least of said intermediate portion of said conduit section being located within the upper portion of said casing, said conduit section being at least partly bare of the liquid refrigerant at its normal level in said casing, and being positioned with said bare portion thereof directly beneath said inlet intercepting the liquid rcfrigerant flowing into said casing via said inlet, said conduit section being connected at its ends into the hot gas defrost line of said apparatus.

References Cited in the file of this patent UNITED STATES PATENTS 

